Field of the Invention
The present disclosure generally relates to methods and apparatus for coupling a top drive to a tool for use in a wellbore.
Description of the Related Art
A wellbore is formed to access hydrocarbon bearing formations, e.g. crude oil and/or natural gas, by the use of drilling. Drilling is accomplished by utilizing a drill bit that is mounted on the end of a tubular string, such as a drill string. To drill within the wellbore to a predetermined depth, the drill string is often rotated by a top drive or rotary table on a surface platform or rig, and/or by a downhole motor mounted towards the lower end of the drill string. After drilling to a predetermined depth, the drill string and drill bit are removed, and a section of casing is lowered into the wellbore. An annulus is thus formed between the string of casing and the formation. The casing string is temporarily hung from the surface of the well. The casing string is cemented into the wellbore by circulating cement into the annulus defined between the outer wall of the casing and the borehole. The combination of cement and casing strengthens the wellbore and facilitates the isolation of certain areas of the formation behind the casing for the production of hydrocarbons.
Top drives are equipped with a motor for rotating the drill string. The quill of the top drive is typically threaded for connection to an upper end of the drill pipe in order to transmit torque to the drill string. Conventional top drives also threadedly connect to tools for use in the wellbore. An operator on the rig may be required to connect supply lines, such as hydraulic, pneumatic, data, and/or power lines, between conventional top drives and the tool complete the connection.
In the construction and completion of oil and gas wells, a drilling rig is used to facilitate the insertion and removal of tubular strings into a wellbore. Tubular strings are constructed by inserting a first tubular into a wellbore until only the upper end of the tubular extends out of the wellbore. A gripping member close to the surface of the wellbore then grips the upper end of the first tubular. The upper end of the first tubular has a threaded box end for connecting to a threaded pin end of a second tubular or tool. The second tubular or tool is lifted over the wellbore center, lowered onto or “stabbed into” the upper end of the first tubular, and then rotated such that the pin end of the second tubular or tool is threadedly connected to the box end of the first tubular. However, it is critical not to damage the threads when the pin end is stabbed into the box end, or when torque is applied to overcome the weight of the second tubular resting on the threads. It is also critical that the drilling rig operator lowers the second tubular at the same rate at which the threads draw together.
The threaded connection between conventional top drives and tools allows only for rotation in a single direction. Manual connection of supply lines can be time-consuming and dangerous to rig personnel. Therefore, there is a need for improved apparatus and methods for connecting top drives to tools.